24. ATHEROSCLEROSIS

Introduction

Arteriosclerosis refers to the thickening and stiffening of the arteries, which reduces blood flow to organs and tissues. When plaque made of fat, cholesterol and cellular waste accumulates inside the artery walls, the arteries become narrow and hard. This condition can progress into atherosclerosis, which is more dangerous.

Atherosclerosis can lead to heart disease, stroke, circulation problems in arms and legs, aneurysms that may bleed internally, and chronic kidney failure. The heart is the most commonly affected organ, but the disease can occur anywhere in the body.

Causes

Several factors contribute to the development of arteriosclerosis and atherosclerosis:

  • High cholesterol levels
  • High blood pressure
  • Insulin resistance or diabetes
  • Obesity
  • Smoking or tobacco use

Family history also increases the risk of developing arteriosclerosis and atherosclerosis.

Symptoms

  • Chest pain or angina
  • Pain in legs or arms due to blocked arteries
  • Shortness of breath
  • Fatigue or tiredness
  • Confusion (when blood flow to brain is affected)
  • Weakness of leg muscles due to poor circulation

Pathophysiology

The disease begins when the innermost layer of the artery, called the intima, fills with fatty deposits and cellular waste products. As these deposits increase, the artery wall becomes thick, stiff and narrow. Different types of arteriosclerosis can develop:

1. Arteriolosclerosis

Affects small arteries and arterioles. These vessels supply nutrients and oxygen to tissues. Thickening of their walls reduces blood flow.

2. Atherosclerosis

This is the most common type and affects medium and large arteries. Plaques composed of cholesterol, fatty substances, calcium, fibrin and cellular waste accumulate inside the artery walls. This causes narrowing and hardening of the arteries, reducing blood supply.

3. Monckeberg’s Arteriosclerosis

Common in elderly patients. Calcium deposits form in the muscular layer of arteries, particularly in the arms and legs.

4. Hyperplastic Arteriosclerosis

Seen in severe hypertension. It affects small and medium-sized arteries, causing thickening of the vessel wall.

5. Hyaline Arteriosclerosis

Characterized by deposition of homogeneous hyaline material in arterioles. Common in diabetic and elderly individuals.

Arteriosclerosis Subtypes

Certain related conditions include:

  • Transplant-related arteriopathy: Thickening of the intima due to immune reactions in transplanted organs.
  • Restenosis after angioplasty or stenting: Arteries may narrow again after treatment.
  • Age-related intimal thickening in arteries like the temporal artery.

In transplant arteriopathy, inflammation affects one or more layers of the artery wall. Later, fibrosis, calcification and thrombosis may occur, further reducing blood flow.

Diagnosis

Doctors use different tests to detect artery blockages and assess heart function:

  • Blood tests: Check cholesterol, fats, sugar and proteins.
  • CT scan: Produces detailed images of the aorta, heart and blood vessels.
  • Electrocardiogram (ECG): Shows electrical activity of the heart and detects enlargement or damage.
  • Stress test: Detects changes in heart rate, blood pressure and rhythm during exercise.
  • Ultrasound: Measures blood flow and detects blockages in arteries of arms and legs.

Treatment

Treatment aims to prevent progression, improve blood flow and reduce complications. This includes lifestyle changes such as a healthy diet, regular exercise and quitting smoking.

Medications used include:

  • Cholesterol-lowering drugs: Reduce plaque buildup.
  • Aspirin: Prevents platelet aggregation and reduces blood clot risk.
  • Beta-blockers: Lower blood pressure and heart rate.
  • ACE inhibitors: Reduce blood pressure and protect heart.
  • Calcium channel blockers: Relax blood vessels.
  • Diuretics: Reduce fluid retention and blood pressure.
  • Clot-busting medicines: Help dissolve dangerous clots.

Complications

If untreated, arteriosclerosis may progress into severe atherosclerosis and lead to serious complications:

  • Coronary artery disease: Leads to angina, heart attack or heart failure.
  • Peripheral artery disease: Causes pain, gangrene and limb amputation.
  • Carotid artery disease: Can cause transient ischemic attack (TIA) or stroke.
  • Aneurysms: Bulging of artery walls that may burst and cause internal bleeding.
  • Chronic renal failure: Narrowing of kidney arteries affects kidney function.

Detailed Notes:

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